Nanoindentation studies of yield point phenomena on gold single crystals

Book · Thu May 01 04:00:00 EDT 1997

OSTI ID:467594

Corcoran, S G; Colton, R J ^[1]; Lilleodden, E T; Gerberich, W W ^[2]

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1. Naval Research Lab., Washington, DC (United States)
2. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science

Nanoindentation studies often show an instantaneous displacement-excursion in the load-displacement curve. This anomaly is generally associated with a surface contamination effect, dislocation emission, a phase transition, or an oxide break-through event. The determination of which effect is operative is often difficult when investigating oxide covered surfaces. The authors have performed a detailed nanoindentation study on clean, flame annealed single-crystal Au thus eliminating the effects of a surface oxide or contamination layer. Multiple displacement excursions were observed exhibiting a new phenomenon of staircase yielding. Owing to the fact that the radius of contact is more than an order of magnitude smaller than the average dislocation spacing expected for well annealed Au, the excursions are explained in terms of multiple dislocation nucleation events on parallel slip bands. Indentation data were taken on Au(111), (110), and (100) single crystal surfaces.

• OSTI ID: 467594
• Report Number(s): CONF-960401--; ISBN 1-55899-339-8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DISLOCATIONS
ELASTICITY
EXPERIMENTAL DATA
GOLD
MONOCRYSTALS
NUCLEATION
PLASTICITY
STRESSES
SURFACE CLEANING
YIELD STRENGTH